Weldability testing of aluminum alloys

Tema ovog diplomskog rada je ispitivanje zavarljivosti aluminijskih legura. U radu su detaljno opisane aluminijske legure (vrste, mehanička svojstva i poteškoće pri zavarivanju). Od poteškoća pri zavarivanju detaljno su razrađene tople pukotine. Opisane su njihove vrste (solidifikacijske i likvacijske) te su objašnjene metode za njihovo ispitivanje (Varestraint, Transvarestraint i Flat tensile). U eksperimentalnom dijelu diplomskog rada istražen je utjecaj dodatnog materijala i parametara zavarivanja na pojavu toplih pukotina kod limova od aluminijske legure AlMg4,5Mn debljine 5 mm. U svrhu istraživanja iz limova su izrezani uzorci za Varestraint metodu ispitivanja. Navedena metoda ispitvanja provedena je na 8 uzoraka, pri različitim unosima topline i s različitim dodatnim materijalima. Nakon provedenog ispitivanja, uzorci su podvrgnuti penetrantskom ispitivanju te su nakon toga iz njih izrađeni makroizbrusici za detaljno analiziranje površine poprečnog presjeka zavara.Subject of this graduation thesis is examination of aluminum alloys weldability. In this thesis aluminum alloys are described in detail (grade, mechanical properties and welding difficulties). Of welding difficulties, special attention was paid on hot cracks. Further are described their types (solidification and liquation) and explained their testing methods (Varestraint, Transvarestraint and Flat Tensile). In experimental part of this thesis is investigated influence of consumable material and welding parameters on appearance of hot cracks in aluminum alloy AlMg4,5Mn sheets 5 mm thick. For puropse of this investigation, sheets were cut in samples for Varestraint method. Mentioned method is used on 8 samples with different heat inputs and different consumable materials. After this method, samples were subdued to penetrant testing. When the penetrant testing was over, samples were cut out for macroscopic examination of welds cross sections